Electric-motor control.



i No. 873,298. PATENTED DEC. 10, 1907.

' w. COOPER. BLBGTRIG'MOTOR CONTROL.

APPLICATION FILED MAR. 3. 1906.

v 'INVENTOR wit/QM ATTORRIEY UNITED STATES PATENT oFFIoE.

WILLIAM co'orns, or WILKINSBURG, PENNSYLVANIA, ASSIGNOR To WESTINGHOUSE ELECTRIC & MANUFACTURING columnar.AcoRroRA'rroNoF PENNSYLVANIA.

- LEcrnro-Morortdonraon To cll'whom it ma cpnc'cmi:

Be it known that I, WILLIAM COOPER, a

citizen .of the United States, anda resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electric- Motor -.Control,-of which-the following 18 a specification.

My invention relates to control systems for electric motors and has special reference to such systems as'embody means for effecting automatic'acceleration of motors.

The object of my invention 1s to provide, 1n a system of the class above indicated, ad-

justable means for retarding the accelerating action that shall be dependent upon a predetermined value of electric current flowing in the motor circuit and means for varying said current-value at the will of the attendant.

' In the operation of variable speedmotors; such as are employed for electric railway vehicle service, it has been found desirable and economical to employ a system of automatic acceleration which has usually comprised a plurality ofswitches so interlocked as to confine their operation 'to a predetermined sequence. With such an arrangement it isadyisable to use a device for preventin the motors may not be iniured by increasing the closure of each accelerating switch untl the currentfiowingin the motor circuit falls below a predeternmied value, in order that the applied voltage too rapidly. A-common form of such a eviee comprises a. magnet coil which is connected in series with the motor circuit and a switch to be actuated thereby. and adapted to interrupt the circuit which supplies energy for operating the accelerating switches. Devices of this character have proved satisfactory when the load on the motor-equipment at starting has been ap roximately constant, as in a single motor ve icle or in a train of vehicles each of which is supplied with an adequate motor equipment; but in control systems for electric locomotiyes which may be called upon to haul variable loads that are dependent upon the length and character of the train, it is desirable to provide'moans for adjusting the redetermined current value. at which the limiting device, will operate in order-"that the time consumed in acoelerati may be kept Ell loads. This cludedin series with themotorcircuit at any one tnnejbut since relatively largecur'rents flow through the moton'circuit, I have pro- 'v ided, by my present invention, means for limiting device shown therein comprises a plurality of switcheshaying' dissimilar actu ating coils, all "of [which are connectedin series relation the motor circuit. T

Referring'to the drawing, a plurality of electric motors comprising armatures 1, 2, 3

-Patented. Dec.10,1907, i

and 4 and field magnet windings 5, 6, .7 and l 8, are supplied with ener from a line conductor 9, the motor circuit 'connectionsbering determined by a plurality of electrically operated,. switches. The action of. these switches is determined by a master controller IOwhich is adapted to occu y a'plurality of 7 positions a, b, wand 1 an through-which energy may be supplied, to the, actuating coils of the switches from abattery 11; 1

The direction of rotation of the'iarmatures of the several motors is determined bya plurality of reversing switches 12, 13, 14, 15,- 16, 17,18and19. t I Y 'When the master controller 10 passes from its ofi, position to the position a, in which *sucomatw acceleration is permitted,

energy is suppliedffrom thegbattery 11' through a contact fin or 20 tocontact ring segments 21 and 22, w 'ch are first engaged by a plurality offingers 23, 24 a'nd 25, the contact ri'ng segment 22 being finally engaged by contact finger 26. ,From the-contact finger 23, energyis supplied through con ductor 27 to the actuating coil of a switch 28,

and the circuit is completed from this point through a conductor 29 which isconnected to'the negative terminal of the battery 11. From the contact finger 24 energy is supplied through a conductor 30 to t e actuat- .1ng coils of switches 12, 15,-1 7 and 18, which determine the direction of rotation of the motors, a ,circuihbeing similarly completed from each one oi -these coils to the negative conductor 29. Energy is su plied from con tact finger 25 to a plurality Qf il 32 and 33 which are eon'neoted series rela-j; tion betwecnthe contact fin er and the n'eg'a-g tive line conductor 29. pee-coils, when? olding coils 31,;

energized, are ada ted to hold a series of switches 34, 35 an 36 in a closed position after they have been moved into such position by hand or otherwise. 5 Energy is supplied from the contact finger 26 through a conductor 37 and through a .-bridging contact mem ber 38, which is located on a switch 39 and is engaged. by a pair of contact fingers 40 and 41, when said switch is inits open circuit position, to an actuating coil of a switch 42, from which point the circuit is completed to the negative battery conductor 29. Byreason of the energizing of the aforesaid actuating coils, the switches 28,

quently, the circuit is completed from the line terminal 9 through switches 28 and 12, armatures 1 and 2, switch 15, field magnet windings 5 and 6, a plurality of dissimilar magnet coils 43, 44, 45 and 46, resistance sections 47 and 48, switch 42, resistance sections 49 and 50, field magnet windings 8 and 7, switch 17, armatures 3 and 4 and switch 18 to an opposite line conductor 51. Thus, it will be observed, the motors are first connected in series relation with resistance sections 47,48, 49 and 50 included in circuit therewith. i When the switch 42 is first closed the our- I rent flowing in the motor'circuit is usually :suiiicient to open part or all of a lurality of switches 52, 53, 54 and 55 whic 1 are actu- -ated',--respectively, by the magnet coils 43, 44, and 46, and, as the counter electroinotive forc'e increases with the speed, the switch is first closed, since its actuating coil 46 comprises fewer convolutions than the coils of switches 54, 53 and 52, which 'clos'e consecutively thereafter, as the current flowing-in the circuit falls below the prede- .te rmined amount at which each switch is ada ted to operate.

en the switches 34, 35 and 36 are open, a circuit connection is completed from the conductor 27 throughswitches 52, 53, 54 and 55,contact finger 56 of the masterswitch 10, contact ring segment 57, contact finger 58, conductor 59, contact fingers 60 and 61 ,which are engaged by abridgin contact member 62 when the switch 42 1s 0 osed, conductor 63, contact fingers 64 and 65, which are engaged by a bridging con tact member 66 when aswitch 67 is open, and through the actuating coil of the switch 67 to the negative line conductor 29.

It will be observed that when the switches 34, 35 and 36 are open the switch 67 cannot be closed to short-circuit the resistance section 47 until the switches 55, 54 53 and 52 are all closed. If, however, the load on the vehicle is such that it is desirable to acceler-- ate the motors more rapidly, the switch 36 may be closed by the attendant. It will be held inthis osition, as hereinbefore explsined, by t e energizing of the cpil 33,

12, 15, 17-, 18 and 42 are closed and, conse,

whereupon energy will be supplied from the conductor 27 through the switch 36 and conductor 68 to a'point between the switches 52 and'53, so that ener may be supplied to the actuating coil of switch 67. In this way, the switch 67 may be closed irrespective of the closing of the switch 52 and, since the actuating coil 43 of the switch 52 contains a greater number of convolutions than any one of the coils 44,45 and 46, the resistance section 47 may be short-circuited-when the current traversing the motor circuit. is at a hi her value than the maximum current va ue at which the acceleration would proceed if the switch 36 were open. In a similar manner, the resistance section .47 may be 'short-circuited at a still higher value of current in the motor circuit by closing the switches 35-and 34, which, in turn, shortcircuit the switches 53 and 54. In each instance, the maximum current-value at which the limiting device will permit the acceleration to proceed is a little higher than that which permitted such procedure when a coil of a greater number of convolutions governed the accelerating circuits.

When the switch 67 is closed, the contact finger 64 is disengaged from the bridging contact member 66 and moves into. engagement with contact member 69, which is also engaged by a contact finger 70, so that the accelerating circuit is now continued from the fin er 64, through the contact member 69 an contact finger 70 to a contact finger 71 of aswitch 72, to short-circuit the resistance section 48. The contact finger 65 of the switch 67 still engages contact member 66, now also enga ed by contact finger 73 which is supplied wit 1 energy directly from the conductor 27 throu 11 contact fingers 74 and 75 that are engaget? by a bridging contact member 76-when the switch 39 is open. In this way, the switch 67, after being closed, is held in this position, irrespective of the limiting device, since its operating coil is now supplied with energy directly from the positive attery termina through the master controller. Thesteps involved in the closure of the switch 67 are repeated for the switch 72 which are ada ted to short-circuit resistance sections 50 and 49, the first step in the opera tion of each switch being dc endent upon the limiting device. When switch 78 is closed, the motors are connected across the line without a resistance included in the circuit. The switch 39 is next closed, ener y being supplied to its actuating coil throug a conductor 79 contact finger'80,.bridging con tact mom er 81, contact finger 82, contact fingers 83 and 84 of a switch 85, which are 2 engaged by a bridging contact member 86 l when'said switch is open, conductor 87 and, Z through the actuating coil'oi the switch 39, l to the negative battery conductor 29.

and for a plurality of switches 77 and 78 115 As soon as the switch 39 is closed, the actuating magnet of the switch 42 becomes deenergized by reason of-the dis-engagement of the contact fingers 40 and 41 from the bridging contact member 38. Furthermore, contact fingers 74 and 75 become dis-engaged from the bridging contact member 76 so that the circuit which has supplied energy for holding the switches 67, 72, 77 and 78 closed, is interrupted, and the switches are opened. The -mot,0r circuit is now completed, from the coils 43, 44, 45 and 46, through switch 39 to field magnet winding 8 so that the circuit connection of the motor remainsthe same,,except that a single shunt short-circuits thesections of resistance, instead of the several shunts hereinbefore described. Y

. When the switch 42 is opened, contact fingers 60 and 61 are dis-engaged from bridging contact member 62. The circuit from the conductor 59 is now continued through contact fingers 88 and 89, which have moved into engagement with a bridging contact member 90, and energy is supplied to operate a switch 91 and also to operate switch 85, the actuating coils of both of-which are immediately transferred from the accelerating circuit to a holding circuit which is independent of the limitin device.

As soon as the'switdh 85 is closed, the contact fingers 83 and 84 become dis-enga ed from the bridging contact member 86 so that the actuating coil of the switch 39 is denergized which permits this switch to open. Circuit is now completed from=the line conductor 9 through ,armatures 1 and '2, field magnet windin s 5 and 6 as before, circuit being completed from this point through the several coils of the limiting device, resistance sections 47 and 48, and switch 91 to thg opposite line conductor 51. Energy is also supplied from the line conductor 9 through switch 85, resistance sections 49 and 50, field magnet windings 8 and 7 and armatures 3 and4 to the opposite line conductor 51. Thus the four motors are connected, two in series, in parallel circuits. When the switch S5 is closed, a plurality of contact fingers 92, 93 and 94 move into engagement with a bridging contact member 95, so that energy is now supplied to finger 64 of the switch 67 and also to the corresponding contact finger of the switch 77. In this way, the switches 67 and 77 are simultaneously closed as soon as the current. traversing the motor circuits falls below a predetermined value, as determined by the limiting device, and a closure of these two switches efi'ects suitable connections for closing the switches 72 and 7b, as soon as the current traversing the motor circuits again falls below a predetermined value. In this way, the resistance included in each of the multiple circuits containing the pairs of motors is simultaneously decreased to *zero and the motors are now connectecbdirectly across the line without resistance in circuit.

When the. controller 10 occupies the osition a: circuits are established similar to t ose which correspond to the position (1 except that, instead of the reversing switches 12, 15, 17 and 18 bein closed, the switches 13, 14, 16 and 19. are c osed so thatthe current traversing the motor circuit passes through the armaturesof the-several motors in the opposite direction. If it, is desirable, at any stage ofthe acceleration of the motors, to prevent an increase in the speed of the veicle, the master controller 10 may be movedfrom the position a to. theposition b or from the position x to the position-y as the case, may be, in which positionsthe contact fingers 56 and 58 become disengaged from the contact ring segments 57 and it is impossible to suppl energy to the conductor 59 from which t e actuating coils of the several switches first receive their energy. The

switches already closed, however, will be retained in such position since all the other circuits are uninterrupted.

If it is desirable to sto the equipment or to interrupt the supply 0 .energy to the motors, the controller 10 ma be moved to the oil position, whenall t e switches .will be 0 en and the holding coils 31, 32 and 33of "t e switches 34, 35 and 36 will be denergized.

In this way, the switches 34,. 35 and 36 .will always automatically open as the vehicleis stopped so thatthey may be'r'egulated each time the vehicle is started to suit the condi-- tions of load existin at that time.

Although I have escribed the limiting arrangement of my invention in connection with a specific system of control, it is obviously not restricted .thereto and may beemployed for use with an sys em of automatic acceleration.

I claim as my invention:

1'. The combination with independently the combination with switches that are adapted to close in a predetermined sequence, of a plurality of limit switches which are adapted to operate at d'iiierent values of electric current and to retard the closure of the said switches.

' 4. in a system of electric motor control,

the combination with switches that are adapted to close in a predetermined se. quence, of limit switches which are adapted to operate at different valuesof electric current and to retard the closure of the said switches, and selective means'for determin ing which of said limit switches shall be included in the circuit.

5. In a system of acceleration-for electric motors, the combination of switches which are electrically interlocked so that their closure is confined to a predetermined sequence, of an adjustable limiting device which automatically interrupts the interconnecting control circuits so that the normal sequential operation is delayed.

6. In a control system, the combination with electric motors, resistance in circuit therewith and switches which are adapted to effect suitable circuit connections and to gradually short-circuit said resistance by the closure of said switches in a predetermined sequence, of an adjustable limiting device which automatically interrupts the inter connecting control circuits so that the normal sequential operation is delayed.

7. In a control system for electric motors, the combination with switches, that are provided with auxiliary interlocking contact members which determine the relative osi-- tion and the sequence of operation 0 the switches, of a plurality of dissimilar magnet windings that are connected in series relation with the'motor circuit and are adapted to open the auxiliary supply circuits when predetermined values of current traverse the motor circuits.

8. The combination with a'plurality of independently operated switches that are adapted to close in a predetermined sequence andan automatic, limiting device which re tards the operation of the switches, of electromagnetic controlling and adjusting means for said limiting device.

9. The combination with a plurality of switches that are adapted to close in a predetermined se uence and an automatic, limiting. device w ich retards the operation of the switches, of a controllin and adjusting means for said limiting revice that com prises manually. operated switches and electro-magnet coi s for holding said switches in position when closed.

. 10. In a control system for electric motors, the combination with independently operj ated switches that are adapted to close in a redetermined sefiience and .an automatic, imitingdevice w ch retards the operation" of the switches and is dependent upon the value of current traversing the motor circuits, of electromagnetic controlling and adj ustingim'eans for said limiting device.

1 1. n a control system for electric motors,

" the combination with switches that are.

adapted to close in a predetermined sequence and an automatic, limiting device which retards the operation of the switches and 1s deprises manuall operated switches and electro-magnet coi s for holding said switches in position when closed. V

- 12. In a system of electric motor control, the combination with switches that are adapted to close in a predetermined sequence, of hniit switches which are adapted to operate at different values ofelectric current and to retard the closure of the switches and selective means for determining which of said limit switches shallbe included inthe circuit, that comprises manuall o erated switches and electro-magnet coi s or holding said switches in position when closed.

13. In a control system, the combination with a plurality of electric motors, resistance in circuit therewith and switches which are adapted to effect suitable circuit connections and to gradually short circuit the resistance by the closure of said switches in a prede'termined sequence and a limiting device which automatically interrupts the interconnectin control circuits so that the normal sequentiail operation. is delayed, of controlling and adjusting means for said limiting device.

14. In a control system, the combination with a plurality of electric motors, resistance in circuit therewith and switches which are adapted to effect suitable circuit connections and to gradually short-circuit the resistance by the closure of said switches in a predetermined sequence and a limiting device which automatically interrupts the interconnectin control circu ts so that the normal sequentia operation is delayed, of controlling and ad justing means for said limiting device that comprises manually operating switches and electro magnet coils for holding said switches in osition when closed.

n testimony whereof, I have hereunto subscribed my name this 23rd day of Febru- 

